1. Field of the Invention
The disclosure relates to an electromagnetic transmission apparatus.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
The transmission of electromagnetic signals and electromagnetic energy can be roughly categorized as wired transmission and wireless transmission. Wired transmission uses all kinds of transmission line as transmission media, such as a coaxial cable or a waveguide. Even though wired transmission exhibits high transmission efficiency, both ends of the transmission line have to be connected to a transmitter and a receiver, and it requires additional space to arrange the transmission line. Both requirements make wired transmission an inconvenience approach. Therefore, most of the current consumer electronic devices utilize wireless transmission.
Unlike wired transmission, wireless transmission does not need a transmission line, and therefore it is a more convenient and versatile approach. However, due to the fact that wireless transmission uses an antenna to transmit and receive electromagnetic waves, and that a typical small-sized antenna broadcasts electromagnetic waves to be transmitted to the air in omni-direction, the antenna at the receiver can only receive a portion of the transmitted electromagnetic power while most of the transmitted electromagnetic power are scattered in the air.
Another wireless transmission is the point to point near-field coupling. Point to point near-field coupling requires electromagnetic coupling elements at the transmitter and the receiver. The electromagnetic coupling element at the transmitter has to be in a certain range and position relative to the electromagnetic coupling element at the receiver for the electromagnetic signals and electromagnetic energy to be transmitted. The examples of point to point near-field coupling applications include photo transmission for digital cameras and electric toothbrush charging. Point to point near-field coupling transmission does not need a transmission line and has exhibits very high transmission efficiency when the transmission distance is relatively short. However, the position alignment of coupling elements requirement limits the transmission range of electromagnetic signal and energy.
U.S. Pat. No . 6,959,450B1 discloses a device for non-contact transmission of electrical signals and/or energy between two parts mobile relative to each other. Such device is suitable for semi-fixed structure, such as shaft or slide rail. Each part of the device is constituted of a plurality of coupling devices connected to a conductor segment or structure. Electromagnetic energy is fed into the segment or the structure, and the end terminal of the device is connected to a load to reduce the energy reflection from the signal fed terminal.
U.S. Pat. No. 6,856,788B2 discloses a wireless IC connection method and system. The capacitance coupler of the transceiver of the system couples electromagnetic energy to a waveguide structure, such as a micro-strip line or coplanar waveguide transmission line, and the electromagnetic energy propagates along the waveguide structure to achieve the objective of electromagnetic energy transmission. This system uses termination resistors at each terminal to reduce the signal reflection.
This system also uses capacitance couplers at a specific location of the waveguide structure as the feed points of electromagnetic energy.
Areisteidis Karalis et al. published an essay “Efficient wireless non-radiative mid-range energy transfer” in 27 Apr. 2007 disclosing a method for electromagnetic energy transmission. Such method uses two non-radiative resonance structures to achieve the objective of electromagnetic energy transmission.
One application of this disclosure provides an electromagnetic transmission apparatus, which does not need a transmission line to achieve the objective of electromagnetic energy and signal transmission.